We present the review of fundamental parameters and properties of metalloporphyrins/phthalocyanines with axial covalent M-O/M-N bonds (M is a metal atom in the oxidation degree more than 2+) for use in the development of the chemistry of molecular materials. The porphyrin complexes covalently bonded along the axial axis are differed by the high oxidation state of a metal atom and related heightened axial reactivity compared with the corresponding derivatives of two charged metal cations, applications of which in both scientific studies and practical areas are most widely reflected in publications. The selection of chemical structures of the 3d, 4d, 5d, and 4f metal derivatives of porphyrins/phthalocyanines and study of their properties promising in the detection of bioactive organic bases, optoelectronics (active components of allsmall molecular organic solar cells), and spintronics (room-temperature magnetocaloric materials) are detailed in the article. The results of the first critical analysis of this topic in the review and the insight into chemical structure effects in the function of MPXs/MPcXs as molecular materials will contribute to further development of their organometallic chemistry.